The invention relates to an assembly of a substrate measurement system.
Such a cluster tool is known from WO 99/49500, in which, in order to reduce cycle time overhead, an inspection tool (e.g. a optical microscope) and one or more review tools (e.g. a scanning electron microscope and/or an atomic force microscope) are linked by an automation platform that handles wafer transport between the tools and a substrate container interface. Although the cluster tool is designed to be optimised with respect to the throughput from one tool (e.g. inspection) to another (e.g. one of the provided review tools), the flexibility of the cluster in terms of maintenance and repair of one of the tools is low: in such a case the complete cluster will be out of order. Also, flexibility in terms of reconfiguring a cluster tool on-site for a different type of wafer analysis, by just a simple replacement of the measurement tools is low.
It is the objective of the present invention to provide a solution for these problems by a more flexible arrangement of the measurement tools and the substrate transfer means involved.
The present invention relates to an assembly of a substrate measurement system in which a second measurement chamber is provided, which fits within the same dimensions as a first measurement chamber. Further, the second measurement chamber is provided with the same identical interface as the first measurement chamber to replace the first measurement chamber.
The present invention provides a substrate measurement system comprising a central substrate handling chamber which is provided with substrate transfer means, at least one substrate container interface with a standardised interface and arranged to receive a matching substrate container, and a mechanical interface to receive a measurement chamber comprising a measurement instrument. The measurement chamber has a standardised size and is provided with standardised mechanical interface, in order to connect to the corresponding interface of the substrate handling chamber. Because of the standardisation of the measurement chamber, the modular substrate measurement system can easily be configured with different types of measurement instruments for a certain application by a simple replacement of one measurement chamber by another chamber.
According to a preferred embodiment of the present invention, the central substrate handling chamber comprises two or more measurement chambers of standardised size and provided with a standardised mechanical interface. In this embodiment, the substrate transfer means are shared by the two or more measurement instruments inside their respective measurement chambers and the substrate container interface, resulting in savings in cost and floor space. Moreover, two or more measurements on a single wafer can be executed sequentially without time delay. In this embodiment, more than one substrate container interface can be connected to the substrate handling chamber. The measurement chambers can be distributed in a substantially horizontal plane but they can also be stacked in a substantially vertical direction.
According to a further embodiment of the present invention, the substrate measurement system comprises a substrate container stocker system arranged to store a plurality of substrate containers, each containing a batch of wafers awaiting measurements, and substrate container transfer means. The substrate container transfer means transfer substrate containers between the stocker system and the substrate container interface of the substrate handling chamber. In this manner, a further increase in efficiency is possible by providing a wafer storage buffer in the stocker system. Due to the physical separation of the functionality of process tools and measurements tools, the delay times in both the process tools and the measurement tools may be reduced since their respective cycle times are no longer dependent on each other.
According to a further embodiment of the present invention, the substrate container interfaces and the mechanical interface of the substrate handling chamber arranged to connect to a measurement chamber are standardised, so that at choice a station can receive either a substrate container or a measurement chamber. In this way, the flexibility of a modular substrate measurement system is increased even further. The system can be adapted to specific needs within a short time. Also, replacement and repair of a measurement chamber containing a defective measurement instrument may be strongly simplified due to the modularity of the system.